POS1449 VALIDATION OF THE GERMAN LUPUSPRO QUESTIONNAIRE TO MEASURE LUPUS-SPECIFIC HEALTH-RELATED QUALITY OF LIFE IN LUPUS ERYTHEMATOSUS PATIENTS
Authors: V. Mevissen, T. Filla, C. Duesing, M. Schneider, J. Meenakshi, G. Chehab
Journal: Annals of the Rheumatic Diseases (2022)

Background To date, there is no validated lupus-specific questionnaire for health-related quality of life (HRQoL) in German language. Regular assessment of health-related quality of life is recommended for monitoring and outcome in current management guidelines [1][2]. Given that about 20% of the EU population are native German speakers, it is therefore essential to validate a Lupus-specific questionnaire in German. Objectives The aim of this study is to present the validity (content, construct, and criterion) and reliability (internal consistency and test-retest) of the German translation of the LupusPro questionnaire, which captures both generic and lupus-specific HRQoL domains. Methods The German LupusPRO was professionally translated and then administered to consecutive patients with systemic lupus erythematosus treated at our tertiary centre. At each visit, clinical and laboratory data were collected, including disease activity and damage (SLEDAI-2K resp. SLICC/SDI). Additional questionnaires were used for validity testing, including questionnaires for HRQoL (SF-36v2), fatigue (FACIT), depression (CES-D), sleep (PSQI) and health impairments (IMET). We calculated Cronbach’s alpha to test reliability. An alpha &gt;0.70 is considered acceptable. Test-retest reliability was tested by evaluating the consistency between the LupusPro at two time points (T0 and T1 after 2-3 days). Criterion and construct validity was assessed by comparing the results of the LupusPRO with the generic HRQoL questionnaire, established clinical endpoints (disease activity, disease damage), and the domains of the additional questionnaires. The confirmatory factor analysis was performed with the Lavaan package (Ver. 0.6-9) in R using the relative fit indices, the Tucker-Lewis index (TLI) and the comparative fit index (CFI). Results 148 patients with confirmed SLE took part in the study of which 111 participated in the test-retest analysis. About 84% were female with a mean age of 45.5 (SD 12.0) and mean disease duration of 17.7 (SD 9.7) yrs. The mean SLEDAI-2K was 3.1 (SD 3.2) and SLICC/SDI 1.4 (SD 2.1). The LupusPro domain’s internal consistency by Cronbach’s alpha exceeded &gt;0.7 except for the domains lupus symptoms (α=0.64), lupus medication (α=0.59), procreative ability (α=0.58), and coping strategies (α=0.43). The overall test-retest correlation was excellent (ICC=0.94). The correlation of the corresponding LupusPRO and SF-36v2 domains were moderate to strong (ρ=0.54–0.78), whereas correlation with disease activity and damage (SLEDAI-2K and SLICC/SDI) was weak (ρ=-0.23 resp. -0.08). Correlation of the selected LupusPRO domains with the above mentioned other dedicated outcome measure instrument emphasized construct and criterion validity. The results of the confirmatory factor analysis showed good construct validity of the LupusPRO. The observed model fit for the hypothesized item-scale relationships was very good (CFI = 0.98, TLI = 0.98). Items generally had loadings of &gt;0.6 with their respective factor. Exceptions were especially the domain coping strategies where all items loaded &lt;0.4. Conclusion The GermanLupusPRO is a valid instrument for measuring health-related quality of life. It shows comparable psychometric properties as the original versions. Minor difference in individual domains may be explained by sociocultural factors. References [1]Gordon C et al. doi: 10.1093/rheumatology/kex286. PMID: 29029350. [2]Fanouriakis A et al. doi: 10.1136/annrheumdis-2019-215089. Disclosure of Interests Veronika Mevissen: None declared, Tim Filla: None declared, Christina Duesing: None declared, Matthias Schneider: None declared, Jolly Meenakshi Consultant of: GSK, Aurinia., Gamal Chehab: None declared